The optical systems that hitherto have been commercially available did not provide the possibility of height adjustment so that in this manner they could be adapted to the various ergonomic requirements of the various users. For optical systems used continuously by a user for eight hours daily or longer, it is essential that the user be able to make an ergonomic adjustment of the optical system including a certain height adjustment relative to the user.
German Patent 101 48 781 discloses a microscope support whereby the microscope can be brought into an ergonomic position for the user. A base plate with adjustable inclination serves simultaneously also as an arm rest. In the center of the base plate is provided a support plate for the microscope with which the arm or hand rests are also firmly connected. The height and the inclination of the microscope can be adjusted. Because the base plate is connected with the support plate, a large number of adjustment steps is needed to obtain the ergonomically most favorable position. In addition, the base plate requires a large floor surface which is detrimental when close-by instrument placement on laboratory tables is needed.
U.S. Pat. No. 5,517,354 discloses an ergonomically adjustable support plate for a microscope. The microscope is firmly mounted on this support plate. To adjust the inclination of the support plate, at least one thread bottom is needed. Hand rests for the user are not provided so that for a height-adjusted microscope, the user must assume an extremely unfavorable hand position. In addition, when the inclination is adjusted, the thread bottom rotates on the support requiring an increased force for the adjustment.
U.S. Pat. No. 2,730,923 shows a microscope which together with the illumination system can be tilted to achieve an ergonomically favorable work position for the user. The microscope itself is fastened to a support plate. The fastening of the microscope to the support plate is achieved with knurled head-screws. In this case, the ergonomic work position can be attained only by tilting the entire microscope and the support disposed on the microscope. For many experiments, tilting the entire microscope is not suitable.
German Patent DE 195 33 934 C1 discloses a locking arrangement for telescope tubes of a height-adjustable stage that can be displaced in one another. To lock the displaceable telescope tubes, there is provided a manually actuated screw spindle which is guided in a thread part disposed on the other tube and which penetrates through the wall of the outer tube. At the end of the screw spindle is disposed an oscillating disk with a washer the large surface of which can be pushed into the wall of the inner tube. As a result, reliable locking of the two telescope tubes can be achieved. The arrangement, however, is not of a compact design.
German Patent DE 100 30 773 C2 discloses an arrangement for linear height adjustment. This arrangement comprises an upright profile with a displaceable telescope the profile of which relative to the upright profile is linearly guided exhibiting only minimal play, with a motor disposed in the telescope profile, with at least two drive gears disposed in the telescope profile and driven by the motor and with at least two concentric drive control guides with which the drive gears engage. Height adjustment by means of a motor is complicated and not well suited for simple and fast adjustment.
German Patent DE 197 47 080 C1 discloses an installation bottom support. The installation bottom support comprises a foot that is height-adjustable by rotation relative to a threaded sleeve. The metallic foot surrounds a thread cooperating with a spherical segment thus providing a height adjustment. The metallic foot is guided in a pedestal in which are present at least two parallel boreholes provided with threaded sleeves for the purpose of taking up the shaft of the foot. The installation bottom support has the drawback that during the adjustment which takes place by rotation, the spherical segments rub against the bottom so that an increased adjustment force is required.